Abonmarche was contracted to intercept stormwater runoff and help alleviate flooding issues in the area including the Crossing Subdivision, MR Realty Property, and the Plymouth Avenue Professional Park (approximately 60 acre drainage area).
The West Goshen – Crossing Subdivision Drainage Improvement Project was designed using a hydraulic and hydrologic analysis to intercept stormwater runoff and help alleviate flooding issues in the area including the Crossing Subdivision, MR Realty Property, and the Plymouth Avenue Professional Park. The improvements consisted of interconnected detention basins with controlled releases into a new storm sewer with discharge to an existing 15-inch culvert under Plymouth Avenue (SR 119). The existing culvert is part of an existing drainage way to the north through Black Squirrel Golf Course and ultimately into the City of Goshen’s municipal storm sewer located on Berkey Avenue north of the golf course. The catchment area of the new detention basins was determined to be 60± acres. The drainage modeling and calculations included existing and future residential development on the subject parcels.
The drainage analysis was performed using 100-year rainfall depths provided by NOAA (National Oceanic and Atmospheric Administration) and using PondPack software by Bentley Software Systems that incorporated a downstream collection pond on the golf course property to evaluate anticipated impacts and flood routing. Due to limited downstream capacity in the existing drainage way, the outfall rate from each detention basin is restricted by an orifice control opening and structure. Several easements for drainage and access were prepared to allow for the new stormwater system to span multiple properties.